Studies On Large Brachiopod Biology And Aquaculture Ii

Author : Shou Hwa Chuang
Publisher :
ISBN 13 : 9781537069982
Total Pages : 382 pages
Book Rating : 4.0/5 (699 download)

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Download or read book Functional Morphology of Brachiopods written by Shou Hwa Chuang and published by . This book was released on 2016-08-12 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book describes the morphology and the functions of the various organ systems of the brachiopods, covering recent lingulids, discinids, craniids, rhynchonellids, terebratulids and terebratellids. It includes the relevant previous publications on the subject and the author's unpublished original observations. Of interest is his illustration of separate periostracum-forming epithelium and skeleton-forming epithelium at the periostracal groove or crypt in Lingula postlarva and Discinisca shelled larva. This serves as an alternative to the interpretation of Williams and Wright (1970) that there was a single epithelium, every individual cell of which moved from the periostracal groove or crypt to the mantle edge like a roller belt and secreted in succession pellicle, periostracum and when it went over the mantle edge, the cell secreted primary layer and finally secondary layer of the skeleton. The author next shows that in the earliest Lingula anatina larva and Discinisca coralliphila shelled larva there was no cuticle connection between the dorsal and the ventral valves, disputing Yatsu's (1902) notion that Lingula valves originated by the bending of a single circular shell. The author's illustration also shows that the intestine and anus of L. anatina larva are present at the 2 p.c. stage after it hatches, disputing Yatsu's (1902) claim that they formed during the 4 p.c. stage. The author also illustrates a rare 10 p.c. L. anatina larva from the Johor Strait with longitudinally divided median tentacle, disproving Yatsu's (1902) notion that the median tentacle atrophied after larval settlement. The author illustrates the differentiation of haemerythrocytes and spindle cells from the mesothelium in the mesothelial ridges of the roof and the floor of the perivisceral cavity, establishing that the spindle cells are a normal constituent of the coelomic fluid and disproving the notion that spindle cells differentiated from muscles fibres. The author spent much time in China, sorting, examining and photographing the exceptionally preserved Lower Cambrian Chengjiang fossils in the various institutions. His revision of the published accounts of them by Chinese palaeontologists and his revision of recent inarticulate brachiopods are presented. It is hoped that his observations and conclusions can earn general acceptance.